Rain has played havoc with the county programme this season, but it has also helped create one of the most open and intriguing championship races in years. With the Liverpool Victoria Championship entering its final month, five teams harbour realistic title ambitions: Sussex and Yorkshire, champions in three of the past six seasons, and Hampshire, Lancashire and Durham, none of whom has captured the prize in modern times.

Yorkshire’s demolition of Warwickshire in Scarborough last week enabled them to return to the top of the table with a 14-point advantage, but they have played one more game than Sussex and two more than the other three sides. They play Sussex at Hove on September 5 and Hampshire at Leeds, in the final round, on September 19.

For all the assistance the damp conditions have given to seam and swing bowling, it is spin that has helped the title-chasers – Durham apart – get where they are. Sussex have Mushtaq Ahmed, Lancashire have Muttiah Muralitharan and Hampshire are led by Shane Warne. Yorkshire’s leading wicket-taker is the promising young leg-spinner, Adil Rashid.

“At the start of the season you think, ‘Who’s the best wizard spinner we can find?’ ” said Rob Key, the Kent captain. “Unfortunately, most of the best are signed up. You can’t write off any county that’s got one. On flat pitches it’s tough to outbowl sides like Sussex. We’ve been in good positions but been unable to nail the win.”

Mark Butcher, the Surrey captain, agrees that spin bowling is key. “Lancashire will miss Murali when he goes [to the Twenty20 world championship]. It’s probably between Sussex and Yorkshire. Yorkshire are more balanced than they used to be. They’re probably the best bowling lineup we’ve faced. Rashid is very handy with bat and ball and very mature. I would take him [on England’s Test tour] to Sri Lanka.”

Key fancies Sussex. “They are my favourites if only because they keep Mushtaq for the rest of the season,” he said. “Yorkshire have a chance, but if the weather were to be dry, Rashid may have to do the job for them that Mushie does for Sussex.”

Mark Robinson, the Sussex coach, says the club sought to recruit bowlers who could perform on any surface. “We have guys who can open up games,” he said. The county’s second overseas player, Naved-ul-Hasan, is one of the best reverse-swing bowlers in the country. He and Mushtaq are the most productive combination in the championship, with 115 wickets in 13 matches.

Hampshire’s chances suffered a blow with an injury to Warne at Old Trafford last Thursday, when, during his 17th over, he pulled up clutching his right side. It transpired he had fractured a rib and he is expected to be out for at least two weeks. Were he to miss the rest of the season, Hampshire’s prospects would surely disappear.

Despite the abandonment of Sussex’s game against Surrey, Robinson says that whatever the outcome, nobody should blame the weather. “The table won’t lie,” he said. “Our guys are quite relaxed, which is good. Tension can get to people. It came into play last year when we gave a couple of edgy performances. Yorkshire will be a big game, but we’ve beaten Lancashire, Hampshire and Durham and know we can beat anyone. Big players rise to big games.”

Sussex began the season slowly, twice losing by an innings, but they have not lost since and showed the resource-fulness of potential champions when they held out for 150 overs to draw with Warwickshire.

Lancashire look as good as anyone, but their all-star cast are rarely available together. Andrew Flintoff won’t play again this season, James Anderson misses the next two games and Murali the last two. If they fail to secure a first outright championship title since 1934, Lancashire might once again look back ruefully on their misfortune with the weather. It has dealt more harshly with them than their rivals, as was the case last year, when they pushed Sussex hard but finished runners-up for the fifth time in nine seasons.

Lancashire have lost only once, at home to Sussex, and their run-in is arguably the easiest, as they avoid Yorkshire, Sussex and Hampshire. But without Murali, taking 20 wickets a match is going to be difficult.

Yorkshire, captained by the ebullient Darren Gough, look better equipped to finish strongly. Michael Vaughan and Matthew Hoggard are both available for the rest of the campaign, and the county moved quickly to replace their original overseas signings, Younis Khan and Jason Gillespie, with Inzamam-ul-Haq and Imran Tahir, a leg-spinner.

Yorkshire once had little time for leg-spin but it is now a central part of their strategy, with Rashid the county’s joint leading wicket-taker along with Gough. They have made much of the running, having started with three wins in four, but faltered when they failed to finish off Hampshire and Kent and were repeatedly frustrated by rain. When they lost to Lancashire and Worcestershire, it seemed they had lost their way, but then came the rout of Warwickshire.

If Yorkshire win, much will be made of their use of imports, particularly the Kolpak signing of Jacques Rudolph, who was playing Test cricket for South Africa only last year. But Stuart Law plays for Lancashire as a naturalised Briton and Sussex have a Kolpak player of their own, Murray Goodwin.

Durham have lost only two whole days to rain, but their luck may be deserting them. Paul Collingwood is away with England, Steve Harmison is out with a back injury and Shivnarine Chanderpaul will miss the last two matches because of the Twenty20 world championship.

“We need to win two of our last four,” said Geoff Cook, Durham’s coach. “As always, you need to find ways to take 20 wickets. The Twenty20 world championship and one-day internationals are causing more disruption than usual and it may benefit Yorkshire. They must fancy their chances.”